Portable or inflatable booster seat

[IdreamedAdreamINtimesGONEby]

I am looking for a booster seat or car “harness” that is as light weight and small as possible. Perhaps an inflatable booster seat?? Or I’ve seen harnesses that strap to the main seat belt and then give a 5 point harness?? I need to carry it around London all day and then use it for around 15 minutes for one journey. So something as cheap and small as possible. Any recommendations?

suitable for 6 year old.

Hoping to find something that I can fit in a small back pack amongst the rest of my stuff I’ll need for the day.

Bubblebum or trunki boostapak

Sorry I’m not sure all i know is I hear the inflatable ones aren’t very safe

Trunki booster pack sounds ideal to me, look on Facebook marketplace for a cheap one. I wouldn’t buy inflatable

Bubblebum boosters are crash tested and really
easy to use

Thanks everyone, will look at those two brands